Smulders last portrayed Hill in "Captain America: The Winter Soldier," where she played a key role in Nick Fury's escape. But with SHIELD destroyed by the end of the film, it was revealed that Hill then took a job with Tony Stark.
TV Line, who broke the news of Smulders' return, is vague about how Hill's position with Stark Industries will draw her back into the SHIELD world.

The site does say that Hill will have a "large role" in the episode, and that she and Coulson will team up with "lots of action." Hill only appeared in the pilot of "Agents of SHIELD," so maybe she will continue exploring the mystery of TAHITI that was first touched upon in that episode.

With Smulders' ties to "How I Met Your Mother" severed, some fans have expressed hope that she should come on to the still-unconfirmed "Agents of SHIELD" Season 2 as a series regular -- or at least be more recurring than she was in Season 1. Her April 29 episode will likely set the stage for how her character will be dealt with in the Marvel Cinematic Universe going forward.

Smulders is far from the only exciting guest star to join the "Marvel's Agents of SHIELD" crew.
Adrian Pasdar and Patton Oswalt will appear in episode 18, "Providence," as Colonel Glenn Talbot (assumedly a HYDRA/SHIELD agent) and Agent Eric Koenig, respectively. Meanwhile,
Amy Acker will play Coulson's former love interest the Cellist, who was first mentioned in "The Avengers." Then, of course, Samuel L. Jackson will be back for the Season 1 finale.

"Marvel's Agents of SHIELD" airs Tuesdays on ABC at 8 p.m. ET/PT. On April 15, episode 18 will air at a special time: 9 p.m. ET/PT.